On 1/11/21 5:14 PM, Dmitry Osipenko wrote:
11.01.2021 16:55, Mikko Perttunen пишет:
Upon a communication error, the interrupt handler can call
tegra_i2c_disable_packet_mode. This causes a sleeping poll to happen
unless the current transaction was marked atomic. Since
tegra_i2c_disable_packet_mode is only called from the interrupt path,
make it use atomic waiting always.

Fixes: ede2299f7101 ("i2c: tegra: Support atomic transfers")
Cc: sta...@vger.kernel.org
Signed-off-by: Mikko Perttunen <mperttu...@nvidia.com>
---
This fixes constant spew for me while HDMI is connected to a
powered off television.

  drivers/i2c/busses/i2c-tegra.c | 16 ++++++++--------
  1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 6f08c0c3238d..4a7ff1840565 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -528,12 +528,12 @@ static void tegra_i2c_vi_init(struct tegra_i2c_dev 
*i2c_dev)
static int tegra_i2c_poll_register(struct tegra_i2c_dev *i2c_dev,
                                   u32 reg, u32 mask, u32 delay_us,
-                                  u32 timeout_us)
+                                  u32 timeout_us, bool force_atomic)
  {
        void __iomem *addr = i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg);
        u32 val;
- if (!i2c_dev->atomic_mode)
+       if (!i2c_dev->atomic_mode && !force_atomic)
                return readl_relaxed_poll_timeout(addr, val, !(val & mask),
                                                  delay_us, timeout_us);
@@ -560,7 +560,7 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
        val |= mask;
        i2c_writel(i2c_dev, val, offset);
- err = tegra_i2c_poll_register(i2c_dev, offset, mask, 1000, 1000000);
+       err = tegra_i2c_poll_register(i2c_dev, offset, mask, 1000, 1000000, 
false);
        if (err) {
                dev_err(i2c_dev->dev, "failed to flush FIFO\n");
                return err;
@@ -569,7 +569,7 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev 
*i2c_dev)
        return 0;
  }
-static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
+static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev, bool 
force_atomic)
  {
        int err;
@@ -579,7 +579,7 @@ static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
        i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
err = tegra_i2c_poll_register(i2c_dev, I2C_CONFIG_LOAD, 0xffffffff,
-                                     1000, I2C_CONFIG_LOAD_TIMEOUT);
+                                     1000, I2C_CONFIG_LOAD_TIMEOUT, 
force_atomic);
        if (err) {
                dev_err(i2c_dev->dev, "failed to load config\n");
                return err;
@@ -684,7 +684,7 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
        if (i2c_dev->multimaster_mode && i2c_dev->hw->has_slcg_override_reg)
                i2c_writel(i2c_dev, I2C_MST_CORE_CLKEN_OVR, I2C_CLKEN_OVERRIDE);
- err = tegra_i2c_wait_for_config_load(i2c_dev);
+       err = tegra_i2c_wait_for_config_load(i2c_dev, false);
        if (err)
                return err;
@@ -707,7 +707,7 @@ static int tegra_i2c_disable_packet_mode(struct tegra_i2c_dev *i2c_dev)
        if (cnfg & I2C_CNFG_PACKET_MODE_EN)
                i2c_writel(i2c_dev, cnfg & ~I2C_CNFG_PACKET_MODE_EN, I2C_CNFG);
- return tegra_i2c_wait_for_config_load(i2c_dev);
+       return tegra_i2c_wait_for_config_load(i2c_dev, true);
  }
static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
@@ -1090,7 +1090,7 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter 
*adap)
              I2C_BC_TERMINATE;
        i2c_writel(i2c_dev, val, I2C_BUS_CLEAR_CNFG);
- err = tegra_i2c_wait_for_config_load(i2c_dev);
+       err = tegra_i2c_wait_for_config_load(i2c_dev, false);
        if (err)
                return err;

What about a simpler variant:

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 6f08c0c3238d..0727383f4940 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -533,7 +533,7 @@ static int tegra_i2c_poll_register(struct
tegra_i2c_dev *i2c_dev,
        void __iomem *addr = i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg);
        u32 val;

-       if (!i2c_dev->atomic_mode)
+       if (!i2c_dev->atomic_mode && !in_irq())
                return readl_relaxed_poll_timeout(addr, val, !(val & mask),
                                                  delay_us, timeout_us);


Yep, I'll post a v2 with that.

Mikko

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